Hexafluoroacetone is becoming an important chemical, which finds use as an intermediate to other fluorocarbon chemicals as well as a monomer in the manufacture of certain fluoropolymers.
The normal commercial process for making hexafluoroacetone requires two steps: (1) chlorination of acetone to hexachloroacetone, and (2) conversion of hexachloroacetone to hexafluoroacetone. Although high-purity product can be obtained in good yields by this process, a cheaper route, requiring only one step, would be highly desirable. Hexafluoropropylene oxide, an industrial perfluorocarbon intermediate, can be isomerized to hexafluoroacetone in the presence of antimony pentafluoride solution as shown in U.S. Pat. No. 3,213,134 to Morin. Although this patent demonstrates the principle, it certainly does not disclose a practical process. The isomerization of hexafluoropropylene oxide was carried out during a period of 20 hours in a sealed glass ampoule at 90.degree. C. A practical process should ideally be capable of continuous, rather than batch, operation; so that isomerization will be virtually instantaneous or at least very fast, rather than time-consuming.